Hi all, I have been using ivtv with MythTV and two Adaptec VideOh PCI cards happily for several years. Recently I upgraded from kernel 2.6.17 with ivtv 0.7.0 to kernel 2.6.24 with ivtv 1.0.3. After upgrading (no change to MythTV), closed captions in new recordings and in live tv were missing many characters. Earlier recordings played back fine. I have since found a solution, but I wanted to ask about it.
Captions were missing character pairs, averaging maybe two or three pairs of adjacent characters per line of caption text. For example, a caption might read "WHERE NOAN HAS GONE BEFE." dropping pairs "space, M" from NO MAN and "O,R" from BEFORE. That's an actual example from the Andromeda Strain broadcast on A&E last week. Sometimes it seems to drop newline characters so a two-line caption appears on one line and runs off the side of the screen. It's not unwatchable, but it's a major nuisance. My hearing isn't very good, and I can't always follow the dialog without captions, even with the volume turned way up. I only found one mention of a similar problem on the lists, at http://www.gossamer-threads.com/lists/ivtv/users/36922#36922 and that one doesn't appear to have been resolved. I upgraded again to kernel linux-2.6.24-gentoo-r8 (from r3) and upgraded to MythTV 0.21 using the tarball from the web site, but nothing helped. My system is an IBM NetVista Pentium 4 at 2GHz running Gentoo Linux with an old nVidia Vanta graphics card and the nvidia driver. I'm in Canada (Toronto) so my cable signal is NTSC. The TV cards both show in lspci as: Multimedia video controller: Internext Compression Inc iTVC16 (CX23416) MPEG-2 Encoder (rev 01) Today I was looking at the source and noticed that function ivtv_vbi_setup in ivtv-streams.c had been changed to use a ringbuffer size of 8 for sliced vbi, where in the older version that worked for me it used 2880/vbi_sliced_size or about 45. It appears the change was made in trac changeset 3488 on 24 October 2006. I tried increasing 8 to 16 and rebuilt my kernel, and now my captions are perfect again. Has anyone else had this problem? Does anyone know of a better fix, or of any undesirable consequences of the change I made? Thanks /Joe _______________________________________________ ivtv-users mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-users
